Buggy code:
@ EActivity ( layout . activity_search ) public class SearchActivity extends AppCompatActivity { @ ViewById protected Toolbar searchToolbar ; @ ViewById protected Spinner sitesSpinner ; @ FragmentById ( id . searchresults_fragment ) protected SearchResultsFragment fragmentResults ; @ ViewById protected ListView searchsitesList ; @ ViewById protected TextView installmoduleText ; @ Bean protected ApplicationSettings applicationSettings ; @ Bean protected SearchHelper searchHelper ; @ SystemService protected SearchManager searchManager ; private MenuItem searchMenu = null ; private SearchRecentSuggestions suggestions = new SearchRecentSuggestions ( this , SearchHistoryProvider . AUTHORITY , SearchHistoryProvider . MODE ) ; private List < SearchSetting > searchSites ; private SearchSetting lastUsedSite ; private String lastUsedQuery ; @ Override public void onCreate ( Bundle savedInstanceState ) { } @ AfterViews protected void init ( ) { <START_BUG> searchToolbar . setNavigationIcon ( abc_ic_ab_back_mtrl_am_alpha ) ; <END_BUG> searchToolbar . setNavigationOnClickListener ( new View . OnClickListener ( ) { @ Override public void onClick ( View v ) { TorrentsActivity_ . intent ( SearchActivity . this ) . flags ( FLAG_ACTIVITY_CLEAR_TOP ) . start ( ) ; } } ) ; setSupportActionBar ( searchToolbar ) ; handleIntent ( getIntent ( ) ) ; if ( ! ( searchHelper . isTorrentSearchInstalled ( ) ) ) { return ; } searchSites = applicationSettings . getSearchSettings ( ) ; lastUsedSite = applicationSettings . getLastUsedSearchSite ( ) ; int lastUsedPosition = - 1 ; if ( ( lastUsedSite ) != null ) { for ( int i = 0 ; i < ( searchSites . size ( ) ) ; i ++ ) { if ( searchSites . get ( i ) . getKey ( ) . equals ( lastUsedSite . getKey ( ) ) ) { lastUsedPosition = i ; break ; } } } if ( ( searchsitesList ) != null ) { SearchSitesAdapter searchSitesAdapter = SearchSitesAdapter_ . getInstance_ ( this ) ; searchSitesAdapter . update ( searchSites ) ; searchsitesList . setAdapter ( searchSitesAdapter ) ; searchsitesList . setOnItemClickListener ( onSearchSiteClicked ) ; if ( lastUsedPosition >= 0 ) { searchsitesList . setItemChecked ( lastUsedPosition , true ) ; lastUsedSite = searchSites . get ( lastUsedPosition ) ; refreshSearch ( ) ; } else { fragmentResults . clearResults ( ) ; } } else { if ( ( getSupportActionBar ( ) ) != null ) getSupportActionBar ( ) . setTitle ( "" ) ; sitesSpinner . setVisibility ( VISIBLE ) ; sitesSpinner . setAdapter ( new SearchSettingsDropDownAdapter ( searchToolbar . getContext ( ) , searchSites ) ) ; sitesSpinner . setOnItemSelectedListener ( onSearchSiteSelected ) ; if ( lastUsedPosition >= 0 ) { sitesSpinner . setSelection ( lastUsedPosition ) ; lastUsedSite = searchSites . get ( lastUsedPosition ) ; refreshSearch ( ) ; } else { fragmentResults . clearResults ( ) ; } } invalidateOptionsMenu ( ) ; } @ Override public boolean onCreateOptionsMenu ( Menu menu ) { } @ Override public boolean onPrepareOptionsMenu ( Menu menu ) { } @ Override protected void onNewIntent ( Intent intent ) { } private void handleIntent ( Intent intent ) { } @ Override public boolean onSearchRequested ( ) { } private OnItemClickListener onSearchSiteClicked = new OnItemClickListener ( ) { @ Override public void onItemClick ( AdapterView < ? > parent , View view , int position , long id ) { } } ; private OnItemSelectedListener onSearchSiteSelected = new AdapterView . OnItemSelectedListener ( ) { @ Override public void onItemSelected ( AdapterView < ? > parent , View view , int position , long id ) { } @ Override public void onNothingSelected ( AdapterView < ? > parent ) { } } ; private String parseQuery ( Intent intent ) { } @ TargetApi ( VERSION_CODES . HONEYCOMB ) @ OptionsItem ( android . R . id . home ) protected void navigateUp ( ) { } @ OptionsItem ( id . action_refresh ) protected void refreshSearch ( ) { } @ OptionsItem ( id . action_downloadsearch ) protected void downloadSearchModule ( ) { } }

Fix:
searchToolbar . setNavigationIcon ( abc_ic_ab_back_material ) ;